KEVIN Keegan was "undoubtedly roughed up" by Yugoslav police at an airport in 1974, according to newly-released official government documents.

He was left with bruises and had blood pouring from his nose after being questioned for 30 minutes by officials in Belgrade.

Papers released by the National Archives reveal an unnamed British diplomat's frustration with the way Yugoslav officials investigated the incident on June 2, 1974, when England arrived to play in a friendly.

The diplomat describes it as a "nasty incident" which erupted after a group of players fooled around at a luggage transporter.

Trouble flared after players moved into a non-customs area and Keegan ignored police orders to move, the papers say.

A day later the Foreign Office official in Belgrade wrote: "He was dragged off for interrogation and undoubtedly roughed up, returning after 30 minutes with a bleeding nose, although not otherwise marked."

A complaint of ill treatment was made, along with a call for an investigation.

"But since Yugoslav police had discovered that he was an international footballer, they had completed a 'full investigation' by last night," the official wrote.

The investigation alleged "that K(eegan) struck a policeman (and) concludes that it is only in the interests of Anglo-Yugoslav relations, international football etc that the police are not pressing well-justified charges against him."

The England players threatened to go on strike in protest, but in the end took to the pitch. Keegan headed the equaliser in a tense 2-2 draw.